Abstract Sustainability is not a new concept. Understanding and seeking it is not only a must but also a challenge for nowadays engineers. Consequently, engineering curricula and faculty should promote on students required knowledge, skills, and behavior to address it. However, such promoting is not a simple task. On the one hand, the several approaches around it may generate ambiguities and misconceptions arising during the engineering design process. On the other hand, a concise but narrow perception of sustainability framing it as environmental care or being able to maintain a business activity over time introduce bias to a proper engineering design process aiming a sustainable development. In fact, it can be argued that there is not a single definition of sustainability suited to all engineering disciplines. In this paper, sustainability is addressed as a software engineering design concern and goal involving multiple dimensions at different moments in time. The presented experience is aimed as a guide for teaching and assessing on sustainability during a software engineering capstone design. It is based on the Karlskrona Manifesto for sustainability design, involving social, individual, environmental, economic, technical dimensions, and considering, short, medium and long-term effects of engineering solutions. A sustainability matrix was used as a tool for analyzing and comparing different software systems designs. Based on the conducted experience, undergraduate students faced a challenge for identifying software systems impacts beyond a short-term time window, whilst graduate students accomplished in a better way such identification process. Learned lessons are shared for the sake of repeatability.